The present invention relates to a lubrication system and its method of operation for use in a rotary engine and, in particular, to an assembly useful in a rotary engine adapted for marine applications.
The rotary internal combustion engine has gained significant acceptance and is being used more widely in automotive applications. One of the major attractions of the rotary engine is the relative simplicity of its construction as compared to more conventional reciprocating piston engines. In addition, advances in engineering technology have eliminated or substantially alleviated certain design and operational problems previously associated with rotary piston engines, such as rotor seal efficiency and life. As a result, additional applications for rotary engines are being evaluated. One particularly attractive application for the rotary engine is marine use and, in particular, in outboard boat motors.
In adapting a rotary engine to an outboard motor, the engine crankshaft or rotorshaft is preferably disposed vertically, as is the crankshaft in a conventional reciprocating piston engine. Similarly as with conventional engines, flywheel is attached to the upper end of the rotorshaft and the lower end of the rotorshaft is attached to a driveshaft which, in turn, extends down into connection with a lower gear case for driving the propeller. As with any other internal combustion engine where a flow of intake air is induced by operation of the engine, the intake of combustion air in a rotary engine may also be induced by engine rotation. The housing of a rotary engine may also often be air cooled or may include a combination of air and water cooling. If air cooling is utilized, cooling air flow is also induced by engine rotation. For the sake of convenience and simplicity of engine construction, a single flow of air is often utilized both for internal cooling of the rotor and for combustion. Thus, after a flow of air is directed through the interior of the engine rotor for cooling, it is directed into the carburetor, mixed with the fuel and passed into the combustion region of the rotor chamber.
In a typical prior art rotary engine construction in which the rotorshaft is horizontally disposed, lubricating oil may be added at opposite ends of the rotorshaft where it is journaled in the ends of the engine block. In addition, lubricating oil may also be mixed with the fuel and introduced therewith into the rotor chamber. The oil in the fuel provides lubrication for the rotor seals, and is then burned with the fuel in the combustion process. In effect, two separate lubrication systems are required, one for supplying oil directly to the main rotorshaft bearings, and another supplying oil mixed with fuel to the rotor chamber. Even in rotary engines which have oil-cooled rotors, oil is additionally intentionally mixed with the fuel to lubricate the rotor seals.
It would be desirable, therefore, to have a single lubricating system requiring only one source of lubricating oil to provide total engine lubrication.